Twitter RSS Feeds – Twitter no longer provides RSS feeds but you can use Google Apps Script to create your own feeds for Twitter timelines, searches and lists.

Google+ RSS Feeds – This Apps Script based Chrome add-on will help you generate RSS feeds for any Google Plus user or even search results. Written by Eric Koleda.

Translate RSS – You can translate foreign language RSS feeds into your native language with Google Scripts and subscribe to them in your favorite news reader.

Gmail Label Feeder – Create a RSS feed for any of your Gmail labels that you can later feed into Evernote, Pocket, etc. through IFTTT. Written by Martin Hawksey.

Gmail Meter – The script will help you analyze how you use Gmail and generates statistics like how much email you send, average length of messages, turn-around time, etc. Written by Romain Vialard.

Gmail Delay Send – While there are browser add-ons that let you schedule emailsin Gmail, the script is easier, safer and your messages will be delivered on a specified date and time. Written by Blair Kutzman.

Gmail Snooze – When you snooze an email, it disappears from view but reappears in the inbox at some specified time in the future. Written by Corey Goldfeder.

Gmail Auto Purge – Similar to auto-sweep in Outlook, the script will automatically delete older email messages from specific senders after a certain period of time.

Gmail Clean-up – Create time-based filters in Gmail that will automatically move, archive or even delete all messages from any particular Gmail label that are older than “n” days. Written by John E. Day.

Save Gmail as PDF – The script will save the body of an email message as a PDF file. You can optionally send the converted PDF to your email address.